How long should a short video be for Reels or Shorts?
Short answer
As short as the idea allows. Many effective brand shorts are 15 to 45 seconds. What matters is that people watch to the end.
Both platforms allow longer short videos than they used to, but length is not a goal. Viewers decide in the first second or two whether to keep watching.
A good rule: cut anything that does not move the viewer towards the payoff. If a 20-second edit says everything, it will usually beat a 60-second one.
See what watch time is and what makes a good hook.